Seismic data processing method for RMO picking

Abstract

The invention relates to a method of processing seismic data, the said seismic data comprising a gather of seismic traces organized according to one or several acquisition parameters, comprising the steps of: a) defining an equation for an RMO curve as a combination of elementary functions of the acquisition parameter(s), b) determining an RMO curve from the equation of step (a) as a combination of orthogonal elementary functions c) for a given time or at a given depth, determining the coefficients of the combination that optimize the semblance of traces along the RMO curve.

1. A method of processing seismic data comprising a gather of seismic traces organized according to one or several acquisition parameters, each seismic trace being a time dependent amplitude signal and being associated with a given position on the ground zone over which the acquisition has been carried out, the method comprising the steps of:
 determining with a computer a residual move-out (RMO) curve by picking in the gather of seismic traces; 
 defining an equation for the RMO curve, as a combination of elementary functions of the acquisition parameter(s); 
 orthogonalizing the elementary functions to determine an RMO curve as a combination of orthogonal elementary functions; 
 for a given time or at a given depth, determining the coefficients of the combination that optimize the semblance of traces along the RMO curve; and 
 processing the seismic traces in view of these coefficients and generating an image of underground geological structures corresponding to the gather of seismic traces. 
 
     
     
       2. A method according to  claim 1 , in which the acquisition parameter(s) is (are) chosen from among the group of parameters consisting of the offset, azimuth angle, incidence angle, source-receiver coordinates. 
     
     
       3. A method according to  claim 1 , in which the step of determining the coefficients is completed for a plurality of sampling times or depths. 
     
     
       4. A method according to  claim 1 , in which the step of orthogonalizing includes a step of normalizing the elementary functions. 
     
     
       5. A method according to  claim 1 , in which the elementary functions are polynomial functions. 
     
     
       6. A method according to  claim 1 , in which the elementary functions are trigonometric functions. 
     
     
       7. A method according to  claim 1 , wherein the seismic data include a plurality of gathers of traces, in which all the steps are carried out independently for each gather of traces. 
     
     
       8. A method according to  claim 7 , including the steps of determining variations of the coefficients as a function of the acquisition parameter(s) on a plurality of gathers of traces and filtering the coefficients. 
     
     
       9. A method of processing seismic data comprising a common mid-point gather organized in accordance with an offset (d), the method comprising the steps of:
 defining an equation for a residual move-out (RMO) curve as a linear combination of elementary functions of the offset of the form f m (d)=d m , where f m  is an elementary function and m is a number between zero and M, with M being a dimension of the elementary functions; 
 orthogonalizing with a computer the elementary functions to determine an RMO curve as a combination of orthogonal elementary functions; and 
 for a given time or at a given depth, determining the coefficients of the combination that optimize the semblance of traces along the RMO curve and generating an image of underground geological structures corresponding to the common mid-point gather. 
 
     
     
       10. A method of processing seismic data comprising a common mid-point gather organized in accordance with an offset (d), the method comprising the steps of:
 defining an equation for an RMO curve as a linear combination of elementary functions of the offset of the form f m (d)=d m , where f m  is an elementary function and m is a number between zero and M, with M being a dimension of the elementary functions; 
 normalizing and orthogonalizing with a computer the elementary functions to determine an RMO curve as a combination of orthogonal elementary functions; and 
 for a given time or at a given depth, determining the coefficients of the combination that optimize the semblance of traces along the RMO curve and generating an image of underground geological structures corresponding to the common mid-point gather. 
 
     
     
       11. A method of processing seismic data comprising a gather of seismic traces organized according to one or several acquisition parameters, each seismic trace being a time dependent amplitude signal and being associated with a given position on the ground zone over which the acquisition has been carried out, the method comprising the steps of:
 receiving the seismic data from a sensor; 
 determining, based on the received seismic data from the sensor, a residual move-out (RMO) curve by picking in the gather of seismic traces; 
 defining an equation for the RMO curve, as a combination of elementary functions of the acquisition parameter(s); 
 orthogonalizing the elementary functions to determine an RMO curve as a combination of orthogonal elementary functions; 
 for a given time or at a given depth, determining the coefficients of the combination that optimize the semblance of traces along the RMO curve; and 
 processing the seismic traces in view of these coefficients curve and generating an image of underground geological structures corresponding to the gather of the seismic traces. 
 
     
     
       12. The method according to  claim 11 , in which the acquisition parameter(s) is (are) chosen from among the group of parameters consisting of the offset, azimuth angle, incidence angle, source-receiver coordinates. 
     
     
       13. The method according to  claim 11 , in which the step of determining the coefficients is completed for a plurality of sampling times or depths. 
     
     
       14. The method according to  claim 11 , in which the step of orthogonalizing including prior to orthogonalizing the step of normalizing the elementary functions. 
     
     
       15. The method according to  claim 11 , in which the elementary functions are polynomial functions. 
     
     
       16. The method according to  claim 11 , in which the elementary functions are trigonometric functions. 
     
     
       17. The method according to  claim 11 , wherein seismic data include a plurality of gathers of traces, in which the steps are carried out independently for each gather of traces. 
     
     
       18. The method according to  claim 17 , further comprising the steps of determining variations of the coefficients as a function of the acquisition parameter(s) on a plurality of gathers of traces and filtering the coefficients. 
     
     
       19. A method of processing seismic data comprising a common mid-point gather organized in accordance with an offset (d), the method comprising the steps of:
 receiving the seismic data from a sensor; 
 determining the common mid-point gather based on the received seismic data; 
 defining an equation for a residual move-out (RMO) curve as a linear combination of elementary functions of the offset of the form f m (d)=d m , where f m  is an elementary function and m is a number between zero and M, with M being a dimension of the elementary functions; 
 orthogonalizing the elementary functions to determine an RMO curve as a combination of orthogonal elementary functions; and 
 for a given time or at a given depth, determining the coefficients of the combination that optimize the semblance of traces along the RMO curve and generating an image of underground geological structures corresponding to the common mid-point gather.